This invention relates to the use of one or more robotic arms in an automated analytical instrument to transport test tubes and other containers or objects between various locations within the instrument and optionally to and from a transport line system in an automated laboratory transport system.
This application is related to the following U.S. patent applications, having the indicated titles, commonly assigned to the Bayer Corporation of Tarrytown, New York and incorporated by reference herein:
(a) design patent applications for Gripper Finger, Ser. No. 29/090,683, filed concurrently herewith; Sample Tube Rack, Ser. No. 29/090,547, filed Jul. 10, 1998; and Sample Tube Rack, Ser. No. 29/089,359, filed Jun. 15, 1998;
(b) utility patent applications for Sample Tube Rack, Ser. No. 08/978,715, filed Nov. 26, 1998; Sample Tube Rack, Ser. No. 09/097,790, filed Jun. 15, 1998; Reagent Package, Ser. No. 08/985,759, filed Dec. 5, 1997; Diluent Package, Ser. No. 29/088,045, filed May 14, 1998; Automatic Handler for Feeding Containers Into and Out of An Analytical Instrument (xe2x80x9cSample Handlerxe2x80x9d), Ser. No. 09/115,391, filed concurrently herewith; Automatic Decapper, Ser. No. 09/115,777, filed concurrently herewith, now U.S. Pat. No. 6,257,091; and Cup Handling Subsystem for an Automated Clinical Chemistry Analyzer System, Ser. No. 09/099,739, filed Jun. 18, 1998.
Robotics have been incorporated into analytical instruments in various ways. The most common use of robotics in these instruments has been to transport a pipette to aspirate liquid from a test tube. Another use of robotics has been to transport a test tube rack within an automated testing system, as described in U.S. Pat. No. 5,260,872.
Robotics have also been used to transport test tubes within an instrument. For example, U.S. Pat. No. 4,835,711 to Hutchins et al. illustrates a robotic arm transporting a test tube to various work stations which are placed in a circle around the robotic arm. The robotic arm is mounted to a fixed position on the workstation and rotates about an axis perpendicular to the surface of the workstation. As illustrated, the test tube appears to be gripped within gripper fingers, the ends of which are curved in the shape of the test tube. No provision is made to transport containers other than test tubes.
Another robotic arm for transporting a test tube is shown in International Publication No. WO 90/03834. This robotic arm rotates and may lift or lower the test tube but the robotic arm is not translatable along any axis. The gripper fingers are only shown and described as gripping a test tube.
U.S. Pat. No. 4,835,707 to Amano et al. describes a robotic arm that is mounted to the central portion of the workstation and articulates in the x, y, and z axes and rotates in the theta direction. The robot may grasp a sample tube or one of various circular nozzles on the workstation with a chuck.
International Publication No. WO 93/15407 describes the movement of a test tube with a robotic arm with a xe2x80x9chandxe2x80x9d to carry the test tube between a mosaic of tesserae of devices and subsidiary devices. The robotic arm may move along a rail in a first axis and a horizontal arm is translatable along second and third axes (vertically and horizontally) and is pivotable about an axis of rotation. This application also teaches that more than one similar apparatuses may be adjoined by and cooperate with another by extending the rails supporting the robots to extend over the adjoining apparatus.
While extending a rail from one apparatus to another similar apparatus is one approach to moving a robotic arm between instruments, this approach is not ideal for transporting objects between more than a few instruments as the rail along which the robotic arm must move becomes significantly long. A better alternative is to use a lab automation transport line to transport test tubes between instruments positioned along the side of the transport line. One such transport line is described in U.S. Pat. No. 5,623,415 to O""Bryan and assigned to SmithKline Beecham Corporation. In the O""Bryan patent, a generic pick-and-place engine, with a robotic arm and grip, is referenced as the means for transferring test tubes between the transport line and the instruments. Alternatively, a pipetting engine may pipette specimens of samples from the test tubes in the transport line for use by the instrument.
It is an object of this invention to provide one or more robotic arms having gripper fingers that may grip and transport individual containers of various types, including various types and sizes of test tubes (including tubes to hold samples, calibrators and controls), customized reagent and diluent packages, dilution cups and pretreatment incubator covers, from a first, source location to a second, destination location. For simplicity, unless otherwise specified, the term xe2x80x9ccontainerxe2x80x9d as used in this application shall include, but not be limited to, objects and each of the foregoing specifically enumerated examples of containers. The robotic arm(s) of the present invention may be advantageously used in a variety of applications, such as a means of transport between modules of a modular automated analytical instrument or between an analytical instrument and a sample transport line.
It is a further object of this invention to provide an analytical instrument that may have at least two robotic arms wherein one of the robotic arms is capable of handling the full workload of the instrument if the other robotic arm is disabled.
It is a further object of this invention to provide a robotic arm that has a first attachment for transporting various types of containers from a first location to a second location in an automated analytical instrument and an interchangeable second attachment for transporting the containers from the instrument to a lab automation system or vice versa.
It is a further object of this invention to provide a service tool, which is used to remove robotic arms easily for replacement and service.
It is a further object of this invention to provide a self-teaching process for the robotic arms to account for slight variations in the locations of areas on the instrument which are addressable.
To achieve these objectives, a robotic arm for an analytical instrument has two translational degrees of freedom, a first along the x-axis and a second along the z-axis, and one rotational degree of freedom in a theta direction about the z-axis. The robotic arm comprises a platform that may move along a rail running above the rear of the instrument and defining the x-axis, a lead screw assembly coupled to the platform and defining the z-axis, a gripper arm coupled to the lead screw assembly to move along the lead screw, grippers mounted to the outer end of the gripper arm, and two gripper fingers. The gripper arm, grippers, and gripper fingers may collectively be referred to as the gripper assembly. The x, z and theta movements are powered by respective servo motors and the grippers are coupled to electronics mounted above the grippers, including an inertia switch and an encoder. An analytical instrument may have at least two of these robotic arms to increase the throughput of the instrument and to provide redundancy in the event that one of the robotic arms fail.
In a first aspect of the present invention, each of the gripper fingers on the robotic arm have upper and lower projections separated by a groove. The grooves allows the fingers to grip and transport various types of containers that have flanges that fit within the grooves, including specialized containers, such as reagent and diluent packages and dilution cups designed for use with the instrument, or other containers with flanges. In addition to capturing the flange, the groove self-aligns a misaligned container as the fingers close around the flange by pushing down on the top of the flange with the bottom of the upper projections and pushing up on the bottom of the flange with the top of the lower projections. The fingers may use the upper and lower projections to grip and transport other containers with cylindrical exterior gripping surfaces, including individual test tubes where the fingers are sufficiently long.
In another aspect of the present invention, the distance to which the fingers separate from one another is limited to a distance smaller than the opening of the grippers. This is preferably accomplished with a rod mounted to one of the fingers, passing through an aperture on the other finger, and ending in a stop, which prevents the fingers from separating more than a desired distance.
In another aspect of the present invention, the robotic arm may have an absolute encoder either coupled to the gripper assembly, the platform, or preferably a separate absolute encoder for each of the gripper assembly the platform to determine whether the robotic arm is in a position where it may be safely homed without hitting an obstruction.
In another aspect of the present invention, because it is desirable in certain situations for the reach of the robotic arm not to extend to some areas of the chassis, the robotic arm may instead reach these locations by inserting a container into or removing a container from a shuttle on the chassis that moves along the y-axis and provides access to at least some of those locations to which the robotic arm cannot reach. The shuttle is preferably a rack that may hold multiple containers.
In another aspect of the present invention, the analytical instrument is designed to be used in conjunction with a laboratory automation system. The instrument has side posts and a gap between the side posts that is large enough to allow the gripper arm to pivot outside of the instrument with a sufficient reach for the fingers to transport test tubes between the transport line of the laboratory automation system and the instrument.
In another aspect of the invention, the platform of the robotic arm is coupled to the rail on the instrument with a bearing plate to simplify the removal of the robotic arm for service or replacement. The service or replacement may be further simplified, in yet another aspect of the invention, with a service tool that is mounted to one side of the instrument. The robotic arm may be transferred from the rail on the instrument to a rail extension on the service tool for easier access.